You might want to define this as being natural or artificial. I'm leaning towards subway lines. Especially if you look at the number of "visitors" per year. The oldest subway is in London. The most beautiful subway is in Moscow. A good, well used, but more plain subway would be the New York Subway. Other places of note: Valley of the Kings near Luxor Egypt & the Tomb of King Tut. The Indian Jones Film made a lasting impression on the world with the Canyon of the Crescent Moon, Petra, Jordan. I'm trying to think of a few caves. Most of them are relatively local and may not have particular national or global interest. The Sea Lion Caves in Oregon is quite interesting.
the most famous space shuttle
Mars is most famous for it's reddish appearance.
what was Apollo greek god most famous for
orion nebula
Archimedes
The most famous place that held gladiator games was the Colosseum.The most famous place that held gladiator games was the Colosseum.The most famous place that held gladiator games was the Colosseum.The most famous place that held gladiator games was the Colosseum.The most famous place that held gladiator games was the Colosseum.The most famous place that held gladiator games was the Colosseum.The most famous place that held gladiator games was the Colosseum.The most famous place that held gladiator games was the Colosseum.The most famous place that held gladiator games was the Colosseum.
howe caverns
Native Americans used to live in lodges. The most famous of them is the Navaho hogan. Earth lodges, generally referred to subterranean dwellings.
whats the most famous canadien place
Carlsbad Caverns in Carlsbad, New Mexico.
Subterranean
Subterranean means underground or hidden. The subterranean cave was filled with water.
what is one famous monument or important place in this
Washington, D.C. is known throughout the world. In my opinion, it is the most famous place in the US.
One of them is Cueva de los Cristales, or Cave of Crystals.
subterranean
subterranean